Taxonomy term

june 2015

The U.S. Geological Survey (USGS) regularly releases National Seismic Hazard Maps that summarize hazards from potential ground shaking produced by faults around the country. This year, for the first time, those maps include not only natural earthquakes, but also earthquakes induced by human activities — particularly injection of wastewater produced during oil and gas extraction practices. The new maps were released Monday on the USGS website.

A humongous hunk of iron — that’s how scientists have long thought of Earth’s solid inner core. But new research suggests there’s more to it than that: namely, that the inner part of the inner core may have different physical properties than the outer part. In addition to revealing a new feature in Earth’s layer-cake internal structure, the discovery may shed light on the planet’s formation, say the authors of the study, published in Nature Geoscience.

Wherever you want to go, the Internet can take you there. Space? No problem. The bottom of the ocean? Sure. Now, you can add another stop to the itinerary: the Mesozoic. A new website, Dinologue.com, aims to transport visitors back to the time of the dinosaurs.

The amount of sediment carried in meandering rivers influences how quickly the bends in those rivers migrate back and forth, according to recent research in Nature Geoscience addressing a longstanding question regarding river evolution. Meanders form when flowing water erodes one riverbank while simultaneously depositing sediment on the opposite bank, gradually creating more and more pronounced U-shaped bends. Sometimes, the rivers cut new channels across the narrow necks of such bends, isolating the abandoned meanders to form distinctive oxbow lakes.

F5VIH. KM3T. PY1NB. These strings of letters and numbers aren’t license plate numbers but call signs. They belong to a handful of Ham radio operators, just three of the more than 2 million amateur enthusiasts whose chatter fills the global airwaves day and night. Now, research suggests these communications may represent a vast trove of data that could help scientists study and monitor space weather.

Levels of the atmospheric pollutant hydrogen chloride have increased substantially in the lower stratosphere over the Northern Hemisphere since 2007, according to a new study. The increase, however, is not due to an influx of chlorine, but rather to a side effect of the recent slowing of stratospheric circulation that was first reported in 2005.

Since first appearing in the fossil record more than 550 million years ago, complex animals have steadily grown in average size, from millimeters to meters to many meters in length. This tendency of species to evolve toward larger sizes over time — known as Cope’s rule — has been studied before in individual species, such as horses and clams, but a new dataset of thousands of marine animals is giving scientists their first large-scale look at how Cope’s rule applies to whole ecosystems over hundreds of millions of years.

As the extreme drought in California persists into another year, EARTH’s regular commentator returns with some thoughts on the proposed solutions, and the wisdom of going “up the hill” to fetch your water.

Gold was highly valued by early civilizations for its scarcity, durability and characteristic color, reminiscent of the sun, which was worshiped by some as a deity. It was first recovered from streambed gravels (placers), where it occurred in native form, and thus did not require extraction from ores. It was both essentially indestructible and easily worked. Gold nuggets were prized possessions that could be fashioned into bars of different standard weights and into ornaments and items of adornment that also served as portable wealth. Gold leaf (gold beaten into thin sheets) has been used to decorate significant architectural structures since ancient times. In the 7th century B.C., the Etruscans used gold to make false teeth, and it is still used in dentistry today due to its nontoxicity, durability and beauty.